Some school kitchen staff are on a "frankly unacceptable" salary despite a recent pay deal.
That is according to the head of a Lisburn primary school, writing in a letter to the Education Authority (EA).
Andrew Burns, from Riverdale Primary, told the EA that his kitchen supervisor had a "pay downgrade".
The EA, which employs the staff in school kitchens and canteens, said that "transformation work" agreed with trade unions was aimed at resolving the issue.
Pay scales for school support workers like bus drivers, classroom assistants and canteen staff were recently changed after a review into pay and job grading.
But as part of that review school kitchen supervisors - known as unit catering supervisors - are on the same pay grade as cooks.
The supervisors have a range of extra duties that cooks are not expected to undertake, including organising menus and food orders, and managing staff.
Some primary schools in County Down have been without hot dinners recently due to a shortage of school kitchen staff.
A spokesperson for the EA said the pay and grading review "significantly reformed the EA pay structures, resulting in an uplift in pay for our support staff".
"This has been widely welcomed by our staff and will go a long way to tackling the recruitment and retention issues we are facing across many of our services."
However, the EA said some pay scales had been merged.
"It was recognised as part of the pay and grading discussions with trade unions that this would have an impact on some staffing structures within our catering service," the spokesperson continued.
"It was therefore agreed with trade unions, as part of the pay and grading negotiations that service transformation work would be undertaken in parallel to the pay scales being amended.
"This would resolve this issue."